@book{151697,
	author = {Armitage, P. and Berry, G. and ebrary, Inc.},
	title = {Statistical methods in medical research},
	publisher = {Blackwell Scientific Publications,},
	year = {2002.},
	address = {Oxford ;},
	edition = {4th ed.},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10232578}
}